Patents Assigned to Alpha and Omega Semiconductor Incorporated
  • Patent number: 9337329
    Abstract: A trenched semiconductor power device includes a trenched gate insulated by a gate insulation layer and surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a semiconductor substrate. The source region surrounding the trenched gate includes a metal of low barrier height to function as a Schottky source and that may include a PtSi, ErSi layer and may further be a metal silicide layer having the low barrier height. A top oxide layer is disposed under a silicon nitride spacer on top of the trenched gate for insulating the trenched gate from the source region. A source contact disposed in a trench opened into the body region for contacting a body-contact dopant region and covering with a conductive metal layer such as a Ti/TiN layer.
    Type: Grant
    Filed: September 8, 2011
    Date of Patent: May 10, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yongzhong Hu, Sung-Shan Tai
  • Patent number: 9318587
    Abstract: Semiconductor power devices can be formed on substrate structure having a lightly doped semiconductor substrate of a first conductivity type or a second conductivity type opposite to the first conductivity type. A semiconductive first buffer layer of the first conductivity type formed above the substrate. A doping concentration of the first buffer layer is greater than a doping concentration of the substrate. A second buffer layer of the second conductivity type formed above the first buffer layer. An epitaxial layer of the second conductivity type formed above the second buffer layer. A doping concentration of the epitaxial layer is greater than a doping concentration of the second buffer layer. This abstract is provided to allow a searcher or reader to quickly ascertain the subject matter of the disclosure with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: May 30, 2014
    Date of Patent: April 19, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Jun Hu, Lingpeng Guan, Hamza Yilmaz, Lei Zhang, Jongoh Kim
  • Patent number: 9318603
    Abstract: The invention relates to a power semiconductor device and its preparation methods thereof. Particularly, the invention aims at providing a method for reducing substrate contribution to the Rdson (drain-source on resistance) of power MOSFETs, and a power MOSFET device made by the method. By forming one or more bottom grooves at the bottom of Si substrate, the on resistance of the power MOSFET device attributed to the substrate is effectively reduced. A matching lead frame base complementary to the substrate with bottom grooves further improves the package of the power MOSFET device.
    Type: Grant
    Filed: March 8, 2014
    Date of Patent: April 19, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yi Su, Daniel Ng, Anup Bhalla, Jun Lu
  • Patent number: 9318424
    Abstract: The present invention discloses the MCSP power semiconductor device and the preparation method thereof. In the present invention method, a metal foil layer is attached to the back of the wafer using a conductive adhesive layer and a composite tape is laminated on the metal foil layer. Thus, individual MCSP power semiconductor devices are separated by cutting the wafer, the conductive adhesive, the metal foil layer and the composite tape along the scribe lines between adjacent semiconductor chips formed on the front of the wafer.
    Type: Grant
    Filed: July 31, 2014
    Date of Patent: April 19, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Zhiqiang Niu, Jun Lu, Hamza Yilmaz, Hongtao Gao
  • Patent number: 9312335
    Abstract: A lateral bipolar transistor includes trench emitter and trench collector regions to form ultra-narrow emitter regions, thereby improving emitter efficiency. The same trench process is used to form the emitter/collector trenches as well as the trench isolation structures so that no additional processing steps are needed to form the trench emitter and collector. In embodiments of the present invention, the trench emitter and trench collector regions may be formed using ion implantation into trenches formed in a semiconductor layer. In other embodiments, the trench emitter and trench collector regions may be formed by out-diffusion of dopants from heavily doped polysilicon filled trenches.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: April 12, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, François Hébert
  • Patent number: 9312381
    Abstract: A lateral superjunction MOSFET device includes a gate structure, a first column connected to the lateral superjunction structure and a second column disposed in close proximity to the first column. The lateral superjunction MOSFET device includes the first column to receive current from the channel when the MOSFET is turned on and to distribute the channel current to the lateral superjunction structure functioning as the drain drift region. The second column disposed near the first column is used to pinch off the first column when the MOSFET device is to be turned off and to block the high voltage being sustained by the MOSFET device at the drain terminal from reaching the gate structure. In some embodiments, the lateral superjunction MOSFET device further includes termination structures for the drain, source and body contact doped region fingers.
    Type: Grant
    Filed: June 23, 2015
    Date of Patent: April 12, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Lingpeng Guan, Karthik Padmanabhan, Hamza Yilmaz
  • Patent number: 9312336
    Abstract: A semiconductor device includes a drain region, an epitaxial layer overlaying the drain region, and an active region. The active region includes: a body disposed in the epitaxial layer; a source embedded in the body; a gate trench extending into the epitaxial layer; a gate disposed in the gate trench; a contact trench extending through the source and at least part of the body; a contact electrode disposed in the contact trench; and an implant disposed at least in part along a contact trench wall; and an epitaxial enhancement portion disposed below the contact trench and in contact with the implant.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: April 12, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Ji Pan, Anup Bhalla
  • Publication number: 20160099238
    Abstract: The present invention discloses anew embedded package comprising: a pre-mold lead frame with a plurality of chips attached thereon, where the molding material fills the voids of the lead frame, no that the lead frame is entirely solid; a plurality of pins arranged around the lead frame; a metal clip attached on and electrically connecting the chips together; first laminate layer which covers the chips, the lead frame, a metal clip and pins; conductive plug and extension formed to connect an electrode of a chip to a corresponding pin or to connect the chips together. The new embedded package of the invention with a three-dimensional stack capacity improves the thickness, thermal and electrical properties and the flexible power and logic hybrid design.
    Type: Application
    Filed: December 10, 2015
    Publication date: April 7, 2016
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Zhiqiang Niu, Hua Pan, Ming-Chen Lu, Yueh-Se Ho, Jun Lu
  • Publication number: 20160099310
    Abstract: The present invention is directed to a method for forming multiple active components, such as bipolar transistors. MOSFETs, diodes, etc., on a semiconductor substrate so that active components with higher operation voltage may be formed on a common substrate with a lower operation voltage device and incorporating the existing proven process flow of making the lower operation voltage active components. The present invention is further directed to a method for forming a device of increasing operation voltage over an existing device of same functionality by adding a few steps in the early manufacturing process of the existing device therefore without drastically affecting the device performance.
    Type: Application
    Filed: December 14, 2015
    Publication date: April 7, 2016
    Applicant: Alpha & Omega Semiconductor Incorporated
    Inventor: Hideaki Tsuchiko
  • Patent number: 9305870
    Abstract: A preparation method for a power semiconductor device includes: providing a lead frame containing a plurality of chip mounting units, one side edge of a die paddle of each chip mounting unit is bent and extended upwardly and one lead connects to the bent side edge of the die paddle and extends in an opposite direction from the die paddle; attaching a semiconductor chip to the top surface of the die paddle; forming metal bumps on each electrode at the front of the semiconductor chip with a top end of each metal bump protruding out of a plane of the top surface of the lead; heating the metal bump and pressing a top end of each metal bump by a pressing plate forming a flat top end surface that is flush with the top surface of the lead; and cutting the lead frame to separate individual chip mounting units.
    Type: Grant
    Filed: October 30, 2015
    Date of Patent: April 5, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Yan Xun Xue, Hamza Yilmaz, Yueh-Se Ho, Jun Lu
  • Publication number: 20160093559
    Abstract: A method of manufacturing a semiconductor package having a small gate clip is disclosed. A first and second semiconductor chips, each of which includes a source electrode and a gate electrode at a top surface, are attached on two adjacent lead frame units of a lead frame such that the lead frame unit with the first chip formed thereon is rotated 180 degrees in relation to the other lead frame unit with the second semiconductor chip formed thereon. A first and second clip sets are mounted on the first and second semiconductor chips, wherein the first clip set is connected to the gate electrode of the first chip, the source electrode of the second chip, and their corresponding leads and the second clip set is connected to the gate electrode of the second chip, the source electrode of the first chip and their corresponding leads.
    Type: Application
    Filed: September 10, 2015
    Publication date: March 31, 2016
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Yan Xun Xue, Hamza Yilmaz, Yueh-Se Ho, Jun Lu, Ming-Chen Lu, Hongtao Gao
  • Patent number: 9293559
    Abstract: Aspects of the present disclosure describe an IGBT device including a substrate including a bottom semiconductor layer of a first conductivity type and an upper semiconductor layer of a second conductivity type, at least one first gate formed in a corresponding first trench disposed over the substrate, and a second gate formed in a second trench disposed over the bottom semiconductor layer. The first and second trenches are provided with gate insulators on each side of the trenches and filled with polysilicon. The second trench extends vertically to depth deeper than the at least one first trench. The IGBT device further includes a body region of the first conductivity type provided between the at least one first gate and/or the second gate, and at least one stacked layer provided between a bottom of the at least one first gate and a top of the upper semiconductor layer.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: March 22, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Jun Hu
  • Patent number: 9293397
    Abstract: A power semiconductor package and a method of preparation are disclosed. The power semiconductor package includes a pair of first and second die paddles arranged side by side, a first semiconductor chip attached to the first die paddle, a second semiconductor chip attached to the second die paddle, a metal clip electrically connecting a first electrode at the top surface of the first semiconductor chip and a first electrode at the top surface of the second semiconductor chip to a second pin, a first conductive structure connecting a second electrode at the top surface of a first semiconductor chip to a first pin, and a second conductive structure connecting a second electrode at the top surface of the second semiconductor chip to a third pin. In examples of the present disclosure, double-chip common source technique for the source electrodes of two power MOSFETs is achieved by applying a T-shape metal clip.
    Type: Grant
    Filed: May 14, 2015
    Date of Patent: March 22, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTORS INCORPORATED
    Inventors: Hamza Yilmaz, Yan Xun Xue, Jun Lu
  • Publication number: 20160079203
    Abstract: A wafer process for molded chip scale package (MCSP) comprises: depositing metal bumps on bonding pads of chips on a wafer; forming a first packaging layer at a front surface of the wafer to cover the metal bumps; forming an un-covered ring at an edge of the wafer to expose two ends of each scribe line of a plurality of scribe lines; thinning the first packaging layer to expose metal bumps; forming cutting grooves; grinding a back surface of the wafer to form a recessed space and a support ring at the edge of the wafer; depositing a metal seed layer at a bottom surface of the wafer in the recessed space; cutting off an edge portion of the wafer; flipping and mounting the wafer on a substrate; depositing a metal layer covering the metal seed layer; removing the substrate from the wafer; and separating individual chips from the wafer by cutting through the first packaging layer, the wafer, the metal seed layers and the metal layers along the scribe lines.
    Type: Application
    Filed: November 24, 2015
    Publication date: March 17, 2016
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Yan Xun Xue, Hamza Yilmaz, Yueh-Se Ho, Jun Lu, Zhiqiang Niu, Guo Feng Lian
  • Patent number: 9287384
    Abstract: A transistor includes a semiconductor body; a body region of a first conductivity type formed in the semiconductor body; a gate electrode formed partially overlapping the body region and insulated from the semiconductor body by a gate dielectric layer; a source diffusion region of a second conductivity type formed in the body region on a first side of the gate electrode; a trench formed in the semiconductor body on a second side, opposite the first side, of the gate electrode, the trench being lined with a sidewall dielectric layer; and a doped sidewall region of the second conductivity type formed in the semiconductor body along the sidewall of the trench where the doped sidewall region forms a vertical drain current path for the transistor.
    Type: Grant
    Filed: February 20, 2015
    Date of Patent: March 15, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Hideaki Tsuchiko
  • Patent number: 9281416
    Abstract: A Schottky diode includes first and second trenches formed in a semiconductor layer where the first and second trenches are lined with a thin dielectric layer and filled partially with a trench conductor layer with the remaining portion being filled with a first dielectric layer. Well regions are formed spaced-apart in a top portion of the semiconductor layer between the first and second trenches. A Schottky metal layer is formed on a top surface of the semiconductor layer between the first and second trenches. The Schottky diode is formed with the Schottky metal layer as the anode and the semiconductor layer between the first and second trenches as the cathode. The trench conductor layer in the first and second trenches is electrically connected to the anode of the Schottky diode. In one embodiment, the Schottky diode is formed integrated with a trench field effect transistor on the same semiconductor substrate.
    Type: Grant
    Filed: September 15, 2014
    Date of Patent: March 8, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Daniel Calafut, Yi Su, Jongoh Kim, Hong Chang, Hamza Yilmaz, Daniel S. Ng
  • Patent number: 9281265
    Abstract: A method of making a semiconductor packaged device comprises mounting onto a lead frame a bottom of a molded semiconductor chip having a first plastic package body covering a top face of a semiconductor chip, encapsulating the lead frame and the semiconductor chip with a second plastic package body with top surfaces of conductive contact bodies electrically connected to electrodes on the top surface of the semiconductor chip exposed and plating conductive pads on a top surface of the assembly structure to provide external electrical connections to the electrodes through the conductive contact bodies.
    Type: Grant
    Filed: September 17, 2014
    Date of Patent: March 8, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yueh-Se Ho, Yan Xun Xue, Jun Lu, Lei Shi, Liang Zhao, Ping Huang
  • Patent number: 9281368
    Abstract: A plurality of gate trenches is formed into a semiconductor substrate in an active cell region. One or more other trenches are formed in a different region. Each gate trench has a first conductive material in lower portions and a second conductive material in upper portions. In the gate trenches, a first insulating layer separates the first conductive material from the substrate, a second insulating layer separates the second conductive material from the substrate and a third insulating material separates the first and second conductive materials. The other trenches contain part of the first conductive material in a half-U shape in lower portions and part of the second conductive material in upper portions. In the other trenches, the third insulating layer separates the first and second conductive materials. The first insulating layer is thicker than the third insulating layer, and the third insulating layer is thicker than the second.
    Type: Grant
    Filed: December 12, 2014
    Date of Patent: March 8, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Lingpeng Guan, Hongyong Xue, Yiming Gu, Yang Xiang, Terence Huang, Sekar Ramamoorthy, Wenjun Li, Hong Chang, Madhur Bobde, Paul Thorup, Hamza Yilmaz
  • Patent number: 9281394
    Abstract: A semiconductor power device may include a lightly doped layer formed on a heavily doped layer. One or more devices are formed in the lightly doped layer. Each device may include a body region, a source region, and one or more gate electrodes formed in corresponding trenches in the lightly doped region. Each of the trenches has a depth in a first dimension, a width in a second dimension and a length in a third dimension. The body region is of opposite conductivity type to the lightly and heavily doped layers. The source region is formed proximate the upper surface. One or more deep contacts are formed at one or more locations along the third dimension proximate one or more of the trenches. The contacts extend in the first direction from the upper surface into the lightly doped layer and are in electrical contact with the source region.
    Type: Grant
    Filed: July 11, 2014
    Date of Patent: March 8, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Daniel Ng, Daniel Calafut, Madhur Bobde, Anup Bhalla, Ji Pan, Yeeheng Lee, Jongoh Kim
  • Publication number: 20160064251
    Abstract: A method to provide a wafer level package with increasing contact pad area comprising the steps of forming a first packaging layer on wafer top surface, grinding the wafer back surface and etch through holes, depositing a metal to fill the through holes and covering wafer backside, cutting through the wafer from wafer backside forming a plurality of grooves separating each chip then depositing a second packaging layer filling the grooves and covering the wafer back metal, reducing the first packaging layer thickness to expose the second packaging layer filling the grooves and forming a plurality of contact pads overlaying the first packaging layer thereafter cutting through the second packaging layer in the grooves to form individual package.
    Type: Application
    Filed: November 5, 2015
    Publication date: March 3, 2016
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Yan Xun Xue